package org.elastic.compreplatform.common.util;
import java.util.Map;

import org.apache.commons.lang.StringUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

/**
 * 以静态变量保存Spring ApplicationContext, 可在任何代码任何地方任何时候中取出ApplicaitonContext.
 */
public class SpringContextUtil implements ApplicationContextAware {

	private static ApplicationContext applicationContext;

	/**
	 * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
	 */
	@Override
	public void setApplicationContext(ApplicationContext applicationContext) {
		SpringContextUtil.applicationContext = applicationContext;
	}

	/**
	 * 取得存储在静态变量中的ApplicationContext.
	 */
	public static ApplicationContext getApplicationContext() {
		checkApplicationContext();
		return applicationContext;
	}

	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 */
	@SuppressWarnings("unchecked")
	public static <T> T params(String name) {
		checkApplicationContext();
		return (T) applicationContext.getBean(name);
	}

	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(Class<T> clazz) {
		checkApplicationContext();
		Map map=applicationContext.getBeansOfType(clazz);
		if(map.size()>=1){
			return (T)map.values().toArray()[0];
		}
		return null;
	}

	private static void checkApplicationContext() {
		if (applicationContext == null){
			throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
		}
	}

	public static <T> T getBean(String beanName) {
		if(StringUtils.isEmpty(beanName)){
			return null;
		}
		checkApplicationContext();
		return (T) applicationContext.getBean(beanName);
	}
}
